internal/static/static.go: remove named error

Change-Id: Idddf6ea9d34f9b51fe6e2c156833fc1c6a6a6964
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/803000
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ethan Lee <ethanalee@google.com>

internal/static/static.go

diff --git a/internal/static/static.go b/internal/static/static.go
index 058e2cb..36c5bdf 100644
--- a/internal/static/static.go
+++ b/internal/static/static.go
@@ -27,7 +27,7 @@
 // when cmd/frontend is run in dev mode and in
 // devtools/cmd/static/main.go with Watch=false for building
 // productionized assets.
-func Build(config Config) (err error) {
+func Build(config Config) error {
 	files, err := getFiles(config.EntryPoint, config.Bundle)
 	if err != nil {
 		return err